It has heretofor been customary as shown in German Pat. No. 19 24 032 and Counterpart British Pat. No. 1,254,673 to utilize a fork shaped end of a steering spindle comprising valve actuator pins having their axes in a plane with the steering spindle axis. These actuator pins protrude into elongated bores in respective valve pistons snugly without play, sliding normal to the steering spindle. The surface of the actuator pins and the surfaces of respective bores, as the steering spindle is rotated, keeps shifting relative the steering spindle axis due to the fixed path of reciprocation of the piston valves relative to the arcuate motion of the actuator pins. During this point of force shifting the valve pistons have about a 20% traverse. Thus, there is friction between the engaged surfaces. In order to avoid valve hysteresis it is necessary to keep the force needed to reciprocate the piston valves as small as possible.